"This is really unprecedented for the chief law enforcement of the United States to come out to California and act more like Fox News than a law enforcement officer," said Brown during a news conference in Sacramento, Wednesday.

"Jeff Sessions just called me an embarrassment. A man whose legacy is targeting immigrants, re-waging the failed War on Drugs, sucking-up to private prison profiteers, and apologizing for white supremacists... I take that as a HUGE compliment," tweeted Newsom.

Democratic leader Nancy Pelosi is also promising action.

"The people of California will not be bowed by the Trump Administration's brazen aggression and intimidation tactics. We will fight this sham lawsuit and will fight all cowardly attacks on our immigrant communities," tweeted Pelosi.

Earlier, Sessions said the Justice Department sued California because state laws are preventing federal immigration agents from doing their jobs.

Jeff Sessions just called me an embarrassment. A man whose legacy is targeting immigrants, re-waging the failed War on Drugs, sucking-up to private prison profiteers, and apologizing for white supremacists... I take that as a HUGE compliment.

The people of California will not be bowed by the Trump Administration's brazen aggression and intimidation tactics. We will fight this sham lawsuit and will fight all cowardly attacks on our immigrant communities. #ProtectDREAMers